Surgical dressing



Patented Sept. 6, .1949

UNITED STATES PATENT OFFICE d y f 2,481,419 'v j' sitGlCL DRESSING William F. Hamilton, Altadeha, Calif., assigner to Frederick M; Turnbull, Los Angeles, Calif.

No irawing.

l claim. (c1. isle-51.5)

This applieatii'i is acer'itinuation in part of copeil'diilg application Serial N; 480,056; filed March 2 3', 1943; fi/elicated surgical dressing and method Aof producing Sallie, which 'al'pli'ca-A tion is n'W' abandoned. l y

Y This invention reiatesto ail improved surgical dressing foriil'ed f'in I'a viscous vsolution and to the solution from which it'- is formed; The liquid is suitable 'lforn oireooapplieatioii to hurried braded, clit, lceiati' 'oi' otherwise injured areas of the body. The liquid contains such ingredients as` to cause it, 1when applied as a coatingr', covering the injured area, to dy to a tough, adherent, continuous', nonraokirig, elast-1o, transparent, wateraresistat `iiflr'rr which is" perspiration permeable, i. e., permeable io the -Water vapor f'riii perspiration. The properties of ade' lllleii'e, cn'tiuity, Wtr'rsslan'c :arid vpri permeability cause the film to promote natiial healing of the 'iriiured area'hyprioteotihg such area rioni 'the 'etaf'rdirig iulluenoe or trauma 'and contamination. The properties of toughnessjaild adherence, together 'with the Aproperjties of its pl'liae and irri'vablit'y, the llri t prornt'e natural lialiiig "of vthe `irlji'ired aea by protecting it fi 'iit'tid and trailiii., Whili might otherwise 'cr ifi tl repeated ielli'val and ieapl'ali io'i I0f V'riv'il'tiljiial g'ze s's ings. Tl YpIities f tglis and elasticity Cause the ilhn to promote V"natural healing' oi the ijrd area iii/hen ia stretches or ntraois during bodily' inoveiiieiitby olosely adhering 'to the iiijuifd aa d'iitinirr'ig its iitiiiu'ity and water-resistance dunne all exparisien and oohtraoiiori. 'i'hogproperty or tiaiis: parey pint the A'natural """ig' l theV iii- Jfure'd area by 'federig it 'cssafy to reiii/' the dressing, and 'ep the iiijiired j'a't the danger f contamination from the air a'drita'- tin and trauma, in order' to observe the prog'- ress of the healing or `Whether" iilftiil has d'eveloped. Thisx property ,and the property oi Water-insolubility 'permit the injured area to be treated ,by hydrtBeapy, and Vflight therapy', Without remvallof the dressing hlm. y, It is an 'object ofthisjiriveutiou' to.I .provide a liquid which may be applied over an injury and which dries rapidlyh i. ina period of a -few miutestoirlna iillr.V l

It is another object of this itito provide a liquid v/'hion ldries e applied whijoh forms a lin which has the liiinbefor described chaiatristits, 'and Whltrli "Supplements theY dsirable prpetls'of illrliilV haltliy' tissue With anti-'bacterial action.

ti1l another objectk of this invention isV to 'provide a liquid adapted i'orrapid evaporationv 'to form a surgical dressing having the attributes described which may be readily removed witlf'loiit injury,- irritation; or trauma to the injured area.

A further object of this 'invention isto provide a surgical dressing which dries to form a non-eraokingwater-'insoluble whioh is irreal- Iicatednin such a 'manner'that the' medicament is totally Yeintractable by Wat-*er1 or body seriali-l' to its use upon the body vand for all types of injuries, and all of them are interdependent.

In the treatment of inany injuries it is highly desirable to apply agents to diminish the lot'v of blood; for example, the shock, and sometimes the fatal result, from severe burns is attributable in a very large measure to the loss of serum from the burned area. The invention contemplates that there may he irl-eluded yirl the surgical dressin'g lio't only one l' incre medicaments-'which are bacteriostatic or bactericidal agents or both; but also one or more Vaso'constrictors which may be effective on the injured area during the application of the liquid and after the dressing has formed. The invention supplements the action ef the vasconstrictor contained in the lm of the surgicaldre'ssing by the exertion of a mechanical pressure which retards the escape of blood -or serumirofn'theiniurd area; this pressure being the result of the attributes oi water-ihsolubility, toiighs's', limited elasticit-:andtenacious ad-4 herence possessed by the iilm.

It has been found that certain siilianilamidetype compounds and salts thereof are highly effective as bacteriostatic and bactericidal agents, and that thiocal application of a vasoconstrictor is very beneiicial in the treatment of many types of injury. It is one' of the particular objects of this invention to provide a surgical dressing which includes one orl more of such compounds. As eiplyd vlfle'rirl the trrr'l sulfanilarnide-type ciipohds" nbaces sulfaiiilamide and the oheiiiohera'heutio ierivatives` anu substitution `products thereof, inter alia, the sulfanilamidf ments, exhibits and adavits in the copending (Methylamino-acetyl) 3, 4 dihydroxy-benzene,`

or kephrine (a-Hydroxy-B-methylamino-ethyl) 3y -7 hydroxybenzene or neo-synephrin (a-Hydroxy-B-methylamino-ethyl)-4 hydroxy- Ibenzene or synephrin fis application Serial No. 445,514, filed June 2, 1942,

now Patent No. 2,478,191 on the application of William F. Hami1ton,'Melvin F. George, Jr., and Eli Simon. One of the desirable attributes of many of the RPs is that they are more soluble Y'K" inwater than are the STCs from which they Y were formed.

(a Hydroxy B-amino-propyl) -benzene`, vorpropadrine y A (a-Hydroxy-B amino propyl) -3, 4-dihydroxybenzene or cobefrin Y f f (B-amino-propyl) -k4-hydroxy -benzene or pare- (B methylamino propyl) -benzene or desoxyephedrine. f Y

Also, for convenience, the symbol STC is employed in the specification to represent a member of the group consisting of (1) Ysulfanilamidetype compounds, and (2) organic salts thereof, and the symbol VA to represent a member of the group consisting "of vasoconstrictive amines and acid-addition salts thereof. Y j

The action of the STC and the VA may be syn-` ergized byy their interaction to form new medic-v inal agents. It has been shown'that the, product formed by the interaction of STC 'and VAl is an amine-(acid-addition) saltl or onium salt of the general formula VR H R wherein C CH;

These products may be described as the .substituted ammonium salts which are the products of the reaction between an' amide and an amine,V

or as the N reaction product of a first compound Inthe treatment of many types of injuries it is desirable that there be available for local action on the body tissues an excess of either STC or vVA` overthat stoichiometric quantity which combineswiththe other so thata greater-bactericidal or bacteriostatic eiectresults fromrthe excess of STC or a greatervasoconstrictive action results from an excessief., thejpf,A V over that obtainable bythe use of REY-withoutl such an excess. The invention contemplates the inclusion in the surgical dressing thereforeY of one or more RPsv wither" without an excess of STCor VA. Y

VIn accordance with the invention theliquid surgical dressing is'fformed of lalbase whichcom tains a plastic andavolatile solventfo'r'the plasl tic and the medicament. hereinafter' point'- ed' out, it Vmay containv also anextraction accelerator 'which',quickensV the, absorption of thermedcamentfrom the dressing lmfby the body V`tis? sues. ,Y n It is necessaryjthat each `of the medicaments which includedfin the surgical dressing be stable in. this'- dressing"` base Lin y the sense that it Y should not 'readily precipitate'therefrom'orV react with the ingredients of. the base to'form toxic,

irritating, ori' otherwise injurious products. It is necessary also that the medicaments be inert with respect to the ingredients of the dressing base'in the sensefthat they do notuimpairthe adherent, tough, continuous, elastic, transparent, water-resistant, A Yperslgiiration-permeable, nonlcracking orpliableattributes ofthe film formed by the evaporationof'the liquid surgical dressing, The term ficompatiblef" as employed herein', mean's'thatjthe medicament to which it is applied possesses these qualities of .stability'and inertness. `Su1fathiazole or sulfanilamide are 'examples of compatible'STCs. Desoxyephedrlne, amphetamineLanl propadrinelare examples of compatibleA `VAs,f Desoxyephedronium Ysulfathiazole, amphetamineniumfI sulfathiazole, and propadronium sulfathiaz'ole are` examples Vof RPS.V Y Y 'j {In the treatment of an injuredarea Ywithan S'IQv, particularly where the treatment is to `be performed by one not a physician, it is desirable menthe rateofsupply ofithe s'rcr to thebody' tissuebe vcontrolled so thatA` it is between themim imumlat which the" bacteria. are destryed' or prevented'from increasing to thefdesired'extent and themaximum Iat, which toxic synrip'to'ms Voccur.Y Similarly, .it is necessaryj in the 'treatment of annjvu'red areaJWith STC, .particu'larlylbycne not a physiciamthat the ,total quantity of STC absorbed? by, the bo'dyjtissueV be controlled bee` tween that minimum necessary forthedesred l'over-all effective bactericidal 'and bacteriosta'tic effect and that maximum inducing symptoms of toxicity. This inventionY provides a surgical dressingcontaining STC, which dressing is oi such nature that it inherently retains between such limits both the rate of availability for absorption of the STC and the total quantity of STC absorbed.v i f It is likewise necessary, particularly when applied yby one not a physician, that'the rate of absorption by the body tissue ofVA be controlled between the minimum at which the required vasoconstrictive effect is secured and that upper limit at which toxicity is induced.` Similarly, it is necessary that the total quantity of VA available for absorption by the body tissue be controlled between that minimum at whichthe over-all re- -quired vasoconstrictive effectv for the required period of timeV is secured and that maximum at which such side effects or other injurious effects are induced.

This invention provides, in its preferred embodiment, a dressing containing a VA, which dressing' is of such character that it invariably controls within such limits both the rate of availability for absorption by the body tissue of the VA and the total quantity of VA available for absorption by the body tissue even when applied by onel not a physician.

When an RP is applied to an injured area, it is necessary that both the rate of availability for absorption by the body tissue and the total quantity available for absorption be controlled between limits defined above for the reasons hereinbefore stated. This invention provides, in its preferred embodiment, a surgical dressing containing an RP, which dressing is of such character that both such rates of absorption and quantity absorbed are invariably controlled bc'- tween such limits, even though applied by one not i an expert.

It is desirable, when an STC is applied to an injured area, that the rate of absorption of STC by the body tissue be varied so that the maximum rate of absorption occurs when and shortly after e the dressing containing the STC is first applied to destroy the infecting organisms then present and so that this rate of absorption diminishes with the passage of time to a minimum as the necessity for the bactericidal and bacteriostatic effect of the STC diminishes with the continuation of the healing process. This invention provides a surgical dressing containing an STC of such character that, no matter how inexpertly it may be applied, the rate of availability of the STC for absorption by the body tissue is so Varied.

When VA is applied to an injured area, it is of great importance that the rate of absorption of VA by the body tissue vary so that it is absorbed at a maximum rate immediately following the application in order to stop quickly the loss of serum or blood conducive to shock, and so that the rate of absorption of VA diminishes very gradually with the passage of time. 'Ihis invention provides a surgical dressing containing VA, which dressing is of such character that such a variation in the rate of absorption of VA by' the body tissue is invariably accomplished.

The rate of absorption of the STC in accordance with this invention is accomplished! .by properly relating the concentration of the STC in the liquid surgical dressing, and hence in the film, with the extractability of the STC bythe body serums. Y

This invention further controls such .rate by the presence of an extraction accelerator. which has the property of increasing the rate of absorption 'of STC by the body tissue.

This invention further controls the quantity of VSIC available for extraction lby the body tissue by properly relating the concentration of .STG in .the liquid and film dressing with the viscosity of ubility, and hence extractability, of each. It controls the total quantity ofVA absorbed by the body tissue by properly relating the concentration of the VA or RP with the viscosity of the liquid dressing, and hence the thickness of the lm. f

- The rate of absorption of STC from the film dressing of this invention is 'diminished withv the passage of time by the decreasing concentration of the STC within the film, since with the STC distributed uniformly throughout the thickness of the 111m the passage of time servesboth to dcrease the quantity of STC available for absorption and to increase the thickness of the lm through which it must be absorbed. The rate of absorption of the STC is also controlled by the effectiveness of the VA which, to the rextent it contracts the vessels, retards such absorption, and by the presence of the extraction accelerator in the nlm. This invention controls the variation in the rate of absorption of STG' by the body tissue through these factors.- l

This invention controls the variation in th rate of absorption by the body tissue of RP and VA by the relation of the concentration of each in the liquid and nlm dressing and the concentration of the extraction accelerator.

A liquid surgical dressing which produces a medicated surgical film in accordance Awith the invention may be formed as set forth 'in the following examples:

Ea'ample 1 parts by volume of a mixed solvent solution is prepared by adding 62 parts of isopropanol to 35 parts of methylethyl ketone and 3 parts of normal butyl acetate. To this solution is added 51/2 partsby weight of pure castor oil, a plasticizer, and 10 parts by weight of pure polyvinyl butyral, a plastic, and the mixture is heated to about to 140 F. with agitation until a clear homogeneous solution is obtained.

d To this solution is added one part by weight of finely powdered sulfathiazole, and the mixture is agitated at a temperature of about 130 to 140 until the drug has completely dissolved.

To this solution is added 0.025 part by weight of tetrabromo-o-cresol an extraction accelerator and finally 0.10 part by weight of desoxyephedronium sulfathiazole finely powdered is added. The mixture is stirred or agitated until the solution is complete and then strained through a suitable strainer, such as cheesecloth, the strained liquid being placed in air-tight bottles for storage and subsequent use.

Example Z If desired, the procedure described maybe modified as follows in order to make approximately one gallon of the solution:

l 320 grams of pure polyvinyl butyral is dissolved in a mixture of isopropanol, 1684 ml., methyl- Vpowderedlsulfathiazole, 34.02 grams, in isopropanol,'-270 ml., and the temperature maintained, as before, during agitation, untiltlie drug is dissolved. f 'Y There is then added av mixture of tetrabromoo-cresol, 0.86 gram; in YisopropanoL-50 ml., and

Vagitation is continued until homogeneity is vcomplete. i VFinallyV lthere, is added separately .1.18 grams of desoxyephedrine baseand 17.6 grams of pure castor oil. The fliquid is stirred,'cooled,`and

v strained4 through a suitable lter into containers.

In both examples giventhere is' an -excess of STC Aover that combining with the VA to form the The proportions of the ingredients may be varied within the following-approximate limits to provide a medicated surgical dressing having to a practical degree all of the attributes hereinb'efore described, the percentage proportions being based upon thenished solution unless otherwise indicated: f. i n

Polyvinyl butyral .'.V 8 to 14% W./v. Castor oil 5,0 to 70% W./w. of resin Butyl acetate 0 to V6% by vol. Isopropanol 60-to 80% by'vol.V VMethylethyl ketone 20 to 40% byfvol. I f

STC` v :.0 to 11/2% w./v.

:VA to 3% by vol.

Tetrabromo-o-cresol 0 toO.25% w./v.`

The liquid ysurgical dressingprepared in accordance with Examples 1 and `2 is light yellow to amber in color and is a clear viscous solution.

After the injured areas are rendered as free from dirt and bacterial contaminationas is possible by the use Aof soap and Water or any recognized and approved practice, andafter the area is thoroughly dried the liquid may be directly applied both to the injured `areas and surround-Y ing tissue, since the liquid is self-sterilizing.

It should be noted, however, that iodine, mercurials, or substances which act as irritants to the tissue are contra-indicated, as their presence under the dressing may'cause .the'injured and covered area Vto become irritated, moist,

' edematousor water-logged.

-' In the preparation of the4 surgical dressing it is'preferred to add the resin to the solvents rst,

vbecause the dissolving of the resin is a relatively slowprocess. It is preferredto add thepca'stor oilv and desoxyephedrine base last 'tol avoid discoloration induced by prolonged heating. It is Vpreferred to formthe desoxyephedronium sulfathiazole in the solution'by the'addition of des- `oxyephedrine base and sulfathiazole instead of adding the desoxyephedronium sulfathiazole to the solution as a'povvder, because this is only sparingly soluble. Y' l Y l Tetrabromo-o-cresol is added in very'small proportions to the medicaments embodied inthe surgical dressing for a' dual purpose. @The compound itself is strong bactericidal, and its presence in the dressing unexpectedly increases the extractability of the sulfathiazole fromk thefilm. It also synergizes the bacteriostatic andbacteri- Vcidal action 'of the sulfathiazole. Actual measurements established that Yabout Y83 toV 90% of the drugs vvere removed kfrom the film produced in ac- 'about 0.2 gram was immersedY in distilled Water at body temperature, 98.6 F. for A2fi hours ;'y whereas, when a filmof exactly the same formulation, except-.that the; tetrabomo-o-cresol V.was omitted, was immersed in water under exactly the same conditions, only about 65% oiqthe drugs were extracted Vfromthelm. Y 1 l;

The presence of the VA in the liquid surgical dressing may l contribute to the extractability of v,the STC from the film by forming acompound Ytherewith which is more soluble in the body liquids contacting the underside of the film than is the STC. y Thus, tests indicate that, under identically the same conditions as dened above, there is extracted about55 of the sulfathiazolawhen `there is omitted from the liquid dressing theVA as Well as the tetrabromo-o-cresol. Y Y n The normal butyl acetate may be entirely omitted from the formulation of Examplesfl and 2 if a slight impairment in the resistance to rupture and wear of the surgical dressing in iilm form is not objectionable. Y

The liquid surgical dressing of Examples 1 and V2 must .be stored in air-tight'containers. For this reason and in order to avoid the contamination of an injured. area by the useoi applicators, such as brushes, rods, or the like, it is preferred to incapsulate the liquidsurgical dressking in prepared gelatin or other materials hav- Water vaporffrom4 the perspiration through the Vli'n under the influence of the continuous evaporation at the outer surface of the film.V It is believed that water. is prevented from passing inwardly through the dressing in lm form by -the absence of Vevaporation atV the inner surface of the film or that the partial pressure of Vthe Water vapor on Ythe inside ofthe film is greater than .theV partial pressure on the outside of the film or both. Itis believed that a medicament, such as an STC in an oil vehicle, when applied to the outer surface of the dressingy in lm form passes through the lm 'because it is an oil-permeable membrane. V Y

The liquid surgical dressing produced in accordance withExamples 1 andr2 dries in avery few minutes when applied to the injured area and forms a Water-resistant, continuous,Y tough, tenaciously adherent. elastic, non-cracking, transparent, perspiration-permeable film. This iilm Vis impermeable to dust, dirt, Yand bacteria. It may include an STC ora VA or. an RP With or Without an excess of STC or of a. VAL vRemedication maybe performed without the removal of the lm by simply applying the desired medicament, preferably in vany oily vehicle, to the exterior of therfilm or by another lapplication vof the liquid surgical dressing whichY softens tion of the dressing in liquid form to soften the film -preliminary to its removal from the area.

The ingredients and their proportions set forth in the preceding examples are effective for burns, abrasions, lacerations, incisions, and similar injuries, and post-operative dressings. 'I'he medicament is absorbed by the body tissue from the film, that nearest the tissue being rst and most rapidly absorbed and that more distant from the tissue being absorbed at a progressively slower rate. This rate of absorption may be increased or decreased as required for most efdcacious treatment of a given injury by increasing or decreasing (or omitting) the concentration of the extraction accelerator, tetrabromo-o-cresol, or the concentration of the VA or both. The total quantity of the medicament absorbed may be increased or decreased by increasing or decreasing its concentration in the surgical dressing or the thickness of the lm. The maximum film thickness obtained by one application or coating is determined by the viscosity of the liquid dressing, and this may be increased or decreased .by Variation of the relative proportions of plastic and solvent.

I claim as my invention:

A liquid containing a dressing base adapted upon a single application for drying to form a continuous, adherent, tough, elastic, non-cracking, Water-resistant, water-insoluble, perspirationand medicament-permeable, transparent, pliable lm, said base including polyvinyl butyral about 8 to 14% W./v. of said liquid, and castor oil about 50 to 70% W./w. of polyvinyl butyral, said liquid containing as a solvent isopropanol about 60 to 80% by volume of said liquid and methylethyl ketone about 20 to 40% by volume of said liquid, said liquid containing in therapeutically beneficial concentration a compatible member of the group consisting of (1) sulfanilamide-type compounds capable of forming organic salts and '(2) Such salts, and said liquid containing as an extractionraccelerator for the medicament tetrabromo-o-cresol in concentration up to about 0.25% w./v. of said liquid.

WILLIAM F, HAMILTON.

REFERENCES CITED The following references are of record in the ille of thispatent: I

UNITED s'r'rEs PATENTS OTHER AaEr'EmsNCEs Archives of Surgery, Dec. 1943, vol. 47, pages 583 to 585. v

Notes on Methyl Ethyl Ketone by Langeduk, Chemistry and Industry, Sept. 1938, pages 891 to Surgery, Gynecologyand Obstetrics, June 1944, page 49 of Ads.

Bull. Johns Hopkins Hospital, Nov. 194.2, Pages 304 to 306.

Ot Practical Interest to Every Practitioner, published by A. De. St. Kalmas 8: Co. Ltd., Leicester, England. Jan. 1942, page 4.

Surgery (St. Louis), October 1942, pages 631 to 534. 'vis Program and Abstracts 'of the Clinical Congress of the American College of Surgeons, Nov. 4 to '1, 1941, page 11. 

